DNA smeared on the side of a space rocket has survived a trip into space and re-entry into the Earth's atmosphere, raising the prospect that life can hop between planets.
Dr Chris Smith from the Naked Scientists told This Way Up's Simon Morton about a study conducted by Zurich University scientist Cora Thiel and her colleagues.
The team applied some DNA to the outside surface of a Texas-49 rocket to see whether any would survive the brief cruise into space. Samples of bacterial DNA, called a plasmid, as well as an antibiotic resistance gene, were painted onto the outer body of the rocket in several places, and also applied to the grooves in the screw heads securing the rocket's skin.
After blast-off the rocket accelerated at up to 17g to reach an altitude of 268 kilometres above the Earth. The total flight time was 780 seconds, about half of which was spent weightless. Sensors inside the rocket showed that the surface during launch and recovery reached temperatures of up to 120 degrees centrigrade.
When the rocket returned to Earth, swabs taken from the DNA test sites showed that up to half of the material recovered was still viable and functional.
With astronaut selection now underway for a manned mission to Mars, Dr Smith says that the findings are important for what's called planetary protection.
"The study shows that DNA can remain stable and functional during even very high-speed, high "g" and high-temperature flight conditions. For this reason, when we send spacecraft and probes to explore distant worlds, careful attention needs to be paid to ensure that pristine alien environments are not contaminated by Earth-originating biological materials. These precautions are taken to a great extent, but there's clearly little room for complacency."